Why can the canopy spell slay the possession?

The crown of the tree has a high status. The reason why Tian Peng's curse can slay the possession is that Tian Peng has a high position in the Northern Song Dynasty, while Tian Peng's curse is a systematic big curse. Its spells are often reversed or read back, that is, one spell becomes several spells. For example, the "Tian Peng curse" is read backwards from the last sentence to the first sentence, which becomes the "Tian Peng curse"; Reading every other sentence backwards becomes a curse of killing demons and swallowing evil. The latter two have the effect of exorcising and killing evil spirits, so this is why Tian Peng curse can kill possessed bodies. This answer is for reference only. Don't be blindly superstitious.